## Issue
Closes 4501 `Font size`
## New behavior
The Desktop app can now zoom the same way as browsers:
- Zoom In: "Ctrl+=" or "Ctrl+numpadPlus" or "Ctrl+WheelUp"
- Zoom Out: "Ctrl+-" or "Ctrl+numpadMinus" or "Ctrl+WheelDown"
- Zoom Reset: "Ctrl+0" or "Ctrl+numpad0"
## Code changes
(1) Electron provides this functionality through the `zoomIn|zoomOut|resetZoom` roles in the Menu, so it would have been a quick job.
However, given that Electron currently does not support having multiple accelerators for one item, we can't add `Ctrl+WheelUp` to the mix and would have to implement our own handler and use `webFrame`.
Given that we need to add code anyways, we handle both keyboard and mouse cases through the same handler, hence the existence of `zoomWindow.js`. It also provides the opportunity to few a few quirks with Electron's default implementation (e.g. stuck at both extremes)
(2) I recall there is another Issue for adding keyboard shortcuts. Given that these shortcuts are universally used in browsers, they are probably "reserved", so shouldn't clash with that task.
bc19503419